The former secretary of state, speaking at a private fundraiser for the Boys and Girls Clubs of Long Beach, said Russian President Vladimir Putin's decision to occupy Ukraine's Crimean peninsula under the pretext of protecting ethnic Russians there is similar to "what Hitler did back in the 1930s." (The Los Angeles News Group posted an audio recording of Clinton's remarks on Wednesday.)

"The ethnic Germans, the Germans by ancestry who were in places like Czechoslovakia and Romania and other places, Hitler kept saying they're not being treated right, I must go and protect my people," Clinton said. "And that's what's gotten everybody so nervous."

Secretary Kerry to meet with Russian counterpart to discuss Ukraine crisisDespite Putin's claims that Russia's intervention was necessary to protect ethnic Russians against attacks by Ukrainian nationalists, Secretary of State John Kerry has emphasized that "not a single piece of evidence supports any of Russia's claims. None."

Clinton also cited Putin's decision to issue Russian passports to Russians in Ukraine as another similarity to Nazi Germany under Adolf Hitler

One attendee told Buzzfeed that Clinton said there is "no indication that Putin is as irrational as the instigator of World War II," but that his actions were still very "destabilizing."

Putin "believes his mission is to restore Russian greatness," Clinton said, according to the Press-Telegram. "When he looks at Ukraine, he sees a place that he believes is by its very nature part of Mother Russia."

Clinton said any negotiation must not sanction Russia's effective annexation of Crimea. "So it's a real nail-biter, right now, but nobody wants to up the rhetoric," she said. "Everybody wants to cool it in order to find a diplomatic solution and that's what we should be trying to do."

Clinton was asked about her historical analogy after a speech on Wednesday at UCLA, and she clarified, "What I said yesterday is that the claims by President Putin and other Russians that they had to go into Crimea and maybe further into Eastern Ukraine because they had to protect the Russian minorities, and that is reminiscent of claims that were made back in the 1930s when Germany under the Nazis kept talking about how they had to protect German minorities in Poland, in Czechoslovakia and elsewhere throughout Europe."

"So I just want everybody to have a little historic perspective," she said. "I'm not making a comparison certainly, but I am recommending that we perhaps can learn from this tactic that has been used before."